Winter cover crops increase readily decomposable soil carbon, but compost drives total soil carbon during eight years of intensive, organic vegetable production in California.

摘要: Maintaining soil organic carbon (SOC) in frequently tilled, intensive vegetable production systems is a challenge that not well understood. Compost and cover crops are often used to add matter the these systems. contributes relatively stabilized (C) while provide readily degradable (labile) matter. Our objectives were quantify C inputs, assess effects of urban yard-waste compost, winter crop frequency type on SOC labile stocks during eight years intensive, usually included two per year long-term study Salinas, California. Total inputs from pelleted fertilizer, transplant potting mix, residue crops, including estimates below ground ranged 40 108 Mg ha-1 five evaluated. Following rapid decline 1, compost had largest effect increasing mean over 2 8 by an average 9.4 ha-1, increased (annual vs. quadrennial) led additional 3.4 increase. In contrast, cropping permanganate oxidizable (POX-C), POX-C 26% after years. Labile was correlated with microbial biomass nitrogen. greatest total stocks, altered composition proportion C. These results suggest frequent has greater potential than increase nutrient availability yields high-input, tillage